Brake testing machine



Patented May 28, 12935 I f invention relates to brake testing ma-`chinespandhas for an object the provision of a.. novel-and unusuallyeiiicient type of machine A`for 'testing vehicle, brakes. I

a -,.A more,detailedf object is the provision of a f roller is adaptedto be revolved by means of a brake testing machine: wherein a wheelengaging driving member threaded axially thereto, with the result thatlongitudinal displacement of the l, driving member occurs in respect tothe roller, in proportion to the resistance to the rollers turning setup by the wheel engaged by the roller.

Another object of the invention is theprovision of a brake testingmachine adapted to generate hydraulic pressure in proportion to theefficiency of the braking mechanism being tested, and also provided with'indicating means responsive to variations of such hydraulic pressure.

A more detailed object is the provision of a brake testing machinecomprising a roller adapted to engage a vehicle wheel and to be rotatedso that the wheel is driven thereby. The means for driving the roller,includes a screw shaft which i is movable longitudinally in respect tothe driven member engaged thereby, and a portion of the shaft isreceived within a closed chamber containing hydraulic fluid, with theresult that the thrust of the shaft resulting from rotational resistanceset up by the driven member, is transmitted into hydraulic pressure, themagnitude of which may be ascertained by any suitable type of indicatingmeans.

Another object is the provision of a brake testing machine operatingupon the above described hydraulic principle, which may be driven in anyone of several manners, there being optionally individual roller drivingmeans, or a common prime mover, coupled to several rollers, it beingunderstood that each of these several rollersv is adapted to engage aseparate wheel of the vehicle.

The invention possesses other objects and advantageous features, some ofwhich, with those enumerated, will be set forthin the followingdescription of the inventions particular embodiment which is illustratedin the drawing accompanying and forming a part of the speciiication.

Referring to the drawing:

The gure is an enlarged, detail vertical sectional View of anothermodified form of the invention.

In terms of broad inclusion, the brake testing machine of the presentinvention, comprises a roller adapted to engage and impart rotationalmovement to a Vehicle wheel, the means for driv. ing the roller being amember threaded axially of the roller, ingmember,

Vonaiiially oflsome interposed drive with the result thatrelativelcngitudinal displacement ,of` the-threaded driving member` andthe :member Idriven thereby, occurs `when resistanceto` the,rollersprotation is set up by the vwheel This displacement; may bemeasured, and from the magnitude, thereof, the eniciency of the brake;withwhich the wheel is pro,-

vided, may be determined.

Referring to the accompanying drawing,

wherein similar reference characters designate similar parts throughout,the invention in its preferred form is disclosed, wherein the roller 33'which is adapted to engage and partially support each of the wheels ofthe vehicle, is provided with an axial bore |26 provided with threads|21 of relatively steep pitch. Threadedly engaged therewith, is a screwshaft 28, the threads |29 of` which are complementary to the threads|21. packing |3| gland nut |32.

shaft |28, is

The screw shaft |28 extends through a compressed about the shaft by a Adriven gear |33 rigid with the enmeshed witha driving gear |34;

and since the shaft |28 will, during operation, move longitudinally the.gear |33 is preferably wider than the driving gear |34,` The gear |34may be connected to any suitable driving means such as a motor |36.-

A duct |31 communicating with the chamber |26, extends throughtheopposite end of the roller 38', and communicates with a conduit |38leading to a pressure indicator |39. The conduit |38 is connected to theroller |31, by any suitable swivel union When the roller 38 is engagedby the wheel in respect to the roller 33'. Of course, this will Vary theeffective capacity ofthe chamber |26, changing the pressure of thehydraulic fluid therein, and

this pressure which is made manifest by the indicating hand |42 of thegauge |39,

' the extent of this movement being proportional disclosed that Vthe endof the driving shaft or r screw bears directly against the fluid whichtransmits the pressure to the pressure indicating device.

By such a construction there is no lost motion between the drivingmember or screw and the liquid.

In this manner the liquid serves a double function of resistinglongitudinal movement of the screw so as to cause it to turn the rollerand, in addition, serves to transmit directly the pressure generated tothe pressure measuring device. f

It is to be understood that the details of the invention as hereindisclosed, are subject to alteration within the spirit or scope of theappended claims.

I claim; .l n

1. In a vehicle brake testing machine, a roller mounted for rotarymovement while in engager' ent with a vehicle wheel, a screw, meansoperatively connecting the screw to said roller to effect turning of theroller by turning the screw, means providing a chamber, said screwextending into and beingmovable longitudinally in respect to thechamber, a uid in the chamber, anda measuring. device communicating withsaid chamber, said measuring device being responsive to pressureYvariations of said iluid.V

2. In a vehicle brake testing machine, a roller mounted for rotarymovement while in engagement with a vehicle Wheel, a screw,meansoperatively connecting the screw to said roller to eifect turningof the roller by turning the screw, said screw having'a portionextending into and being movable longitudinally in vrespect to a chamberwithin said roller, a iluid in the chamber, and-a measuring devicecommunicating with said chamber, said measuring device being responsiveto pressure variations of said fluid.

3. A brake testing machine comprising a wheel engaging roller having alongitudinally axial bore internally threaded therein, a threaded shaftextending into the bore with its threads meshing with the threads of thebore, said' shaft being mounted for rotation and longitudinal movement,means for rotating the shaft, and means resisting longitudinal movementof the shaft with respect to the roller, said means serving to measureforces longitudinally eiective upon the shaft.

v4:. A brake testing machine comprising a wheel engaging roller having alongitudinally axial bore internally threaded therein, a threaded shaftextending into the bore with its threads meshing with the threads of thebore, said shaft being mounted for rotation and longitudinal move.-ment, means for rotating the shaft, a fluid conned in the roller againstthe end of the shaft, and means for measuring the presure developed` inthe uid by the longitudinal movement of the shaft relatively to .theroller.

FRANK P. BUCKLEIN.

